全文获取类型
收费全文 | 12563篇 |
免费 | 724篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 112篇 |
儿科学 | 291篇 |
妇产科学 | 170篇 |
基础医学 | 1693篇 |
口腔科学 | 270篇 |
临床医学 | 1682篇 |
内科学 | 2768篇 |
皮肤病学 | 118篇 |
神经病学 | 1060篇 |
特种医学 | 535篇 |
外科学 | 1556篇 |
综合类 | 62篇 |
一般理论 | 4篇 |
预防医学 | 1039篇 |
眼科学 | 132篇 |
药学 | 872篇 |
中国医学 | 14篇 |
肿瘤学 | 946篇 |
出版年
2024年 | 12篇 |
2023年 | 87篇 |
2022年 | 150篇 |
2021年 | 250篇 |
2020年 | 182篇 |
2019年 | 303篇 |
2018年 | 336篇 |
2017年 | 249篇 |
2016年 | 293篇 |
2015年 | 332篇 |
2014年 | 459篇 |
2013年 | 670篇 |
2012年 | 1041篇 |
2011年 | 1035篇 |
2010年 | 595篇 |
2009年 | 536篇 |
2008年 | 806篇 |
2007年 | 912篇 |
2006年 | 815篇 |
2005年 | 861篇 |
2004年 | 720篇 |
2003年 | 608篇 |
2002年 | 640篇 |
2001年 | 86篇 |
2000年 | 59篇 |
1999年 | 92篇 |
1998年 | 154篇 |
1997年 | 119篇 |
1996年 | 111篇 |
1995年 | 99篇 |
1994年 | 83篇 |
1993年 | 67篇 |
1992年 | 52篇 |
1991年 | 45篇 |
1990年 | 36篇 |
1989年 | 41篇 |
1988年 | 30篇 |
1987年 | 14篇 |
1986年 | 17篇 |
1985年 | 30篇 |
1984年 | 28篇 |
1983年 | 33篇 |
1982年 | 35篇 |
1981年 | 20篇 |
1980年 | 21篇 |
1978年 | 13篇 |
1977年 | 12篇 |
1975年 | 12篇 |
1974年 | 10篇 |
1970年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A case of presumed pontine capillary telangiectasia in an 18-year-old woman with a clinical diagnosis of basilar-type migraine
is reported. Since both are very rare diagnoses, this case provides some evidence to suggest that pontine capillary telangiectasia
might cause a clinical picture resembling basilar-type migraine. 相似文献
992.
993.
Visser WE Jansen J Friesema EC Kester MH Mancilla E Lundgren J van der Knaap MS Lunsing RJ Brouwer OF Visser TJ 《Human mutation》2009,30(1):29-38
Monocarboxylate transporter 8 (MCT8; approved symbol SLC16A2) facilitates cellular uptake and efflux of 3,3',5-triiodothyronine (T3). Mutations in MCT8 are associated with severe psychomotor retardation, high serum T3 and low 3,3',5'-triiodothyronine (rT3) levels. Here we report three novel MCT8 mutations. Two subjects with the F501del mutation have mild psychomotor retardation with slightly elevated T3 and normal rT3 levels. T3 uptake was mildly affected in F501del fibroblasts and strongly decreased in fibroblasts from other MCT8 patients, while T3 efflux was always strongly reduced. Moreover, type 3 deiodinase activity was highly elevated in F501del fibroblasts, whereas it was reduced in fibroblasts from other MCT8 patients, probably reflecting parallel variation in cellular T3 content. Additionally, T3-responsive genes were markedly upregulated by T3 treatment in F501del fibroblasts but not in fibroblasts with other MCT8 mutations. In conclusion, mutations in MCT8 result in a decreased T3 uptake in skin fibroblasts. The much milder clinical phenotype of patients with the F501del mutation may be correlated with the relatively small decrease in T3 uptake combined with an even greater decrease in T3 efflux. If fibroblasts are representative of central neurons, abnormal brain development associated with MCT8 mutations may be the consequence of either decreased or increased intracellular T3 concentrations. 相似文献
994.
Efraim H. Rosenberg Eduard A. Struys Keith Hyland Barbara Plecko Paula J. Waters Saadet Mercimek-Mahmutoglu Sylvia Stockler-Ipsiroglu Renata C. Gallagher Gunter Scharer Johan L.K. Van Hove Cornelis Jakobs Gajja S. Salomons 《Molecular genetics and metabolism》2009,97(4):312-314
This study describes the use of cerebral spinal fluid (CSF) and/or urine as source of DNA for mutation analysis combined with multiple displacement amplification. The findings illustrate the opportunities and pitfalls of these methods in the search for identification of the pathogenic mutations in the case that only scarce material is available such as CSF. 相似文献
995.
Jacomina W. van den Esschert Wilmar de Graaf Krijn P. van Lienden Olivier R. Busch Michal Heger Otto M. van Delden Dirk J. Gouma Roelof J. Bennink Johan S. Laméris Thomas M. van Gulik 《Journal of gastrointestinal surgery》2009,13(8):1464-1469
Introduction Portal vein embolization is an accepted method to increase the future remnant liver preoperatively. The aim of this study
was to assess the effect of preoperative portal vein embolization on liver volume and function 3 months after major liver
resection.
Materials and methods This is a retrospective case-control study. Data were collected of patients who underwent portal vein embolization prior to
(extended) right hemihepatectomy and of control patients who underwent the same type of resection without prior portal vein
embolization. Liver volumes were measured by computed tomography volumetry before portal vein embolization, before liver resection,
and 3 months after liver resection. Liver function was assessed by hepatobiliary scintigraphy before and 3 months after liver
resection.
Results Ten patients were included in the embolization group and 13 in the control group. Groups were comparable for gender, age,
and number of patients with a compromised liver. The mean future remnant liver volume was 33.0 ± 8.0% prior to portal vein
embolization in the embolization group and 45.6 ± 9.1% in the control group (p < 0.01). Prior to surgery, there were no significant differences in future remnant liver volume and function between the
groups. Three months postoperatively, the mean remnant liver volume was 81.9 ± 8.9% of the initial total liver volume in the
embolization group and 79.4 ± 11.0% in the control group (p > 0.05). Remnant liver function increased up to 88.1 ± 17.4% and 83.3 ± 14% respectively of the original total liver function
(p > 0.05).
Conclusion Preoperative portal vein embolization does not negatively influence postoperative liver regeneration assessed 3 months after
major liver resection.
No grant support.
Paper presented at the SSAT, Chicago, June 1, 2009. 相似文献
996.
Mari Hoff Alvilde Dhainaut Tore K. Kvien Kristina Forslind Johan Kälvesten Glenn Haugeberg 《Journal of clinical densitometry》2009,12(1):17-21
Digital X-ray radiogrammetry (DXR) calculates peripheral bone mineral density (BMD) from hand radiographs. The aim of this study was to examine in vitro and in vivo precision for the new direct digital version of DXR, a development of the conventional DXR. The in vitro precision for direct DXR was tested on 4 different X-ray equipments, based on 31 radiographs of the same phantom. The in vivo precision was based on duplicate hand radiographs from both hands in 39 individuals. For the 4 X-ray equipments, in vitro precision ranged from 0.14% to 0.30%, expressed as coefficient of variations (CV%) and from 0.0012 to 0.0028 g/cm2, expressed as smallest detectable difference (SDD). The precision was correlated to the resolution of the radiographic equipment (r = 0.95, p = 0.05). The corresponding values for the in vivo precision for mean values of both hands were: CV% = 0.46%; SDD = 0.0046 g/cm2, and least significant change (LSC%) = 1.28%. The DXR-BMD for 1 of the X-ray equipments differed 1.1% from the overall mean. The precision for direct DXR was highly satisfactory both in vitro and in vivo. DXR-BMD values may differ between the radiographic equipments, and follow-up measurements should be performed with the same X-ray equipment. 相似文献
997.
Erik Nordenström Johan Westerdahl Anders Bergenfelz 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2009,394(3):461-467
Background Primary hyperparathyroidism (pHPT) is associated with decreased bone density and increased fracture risk. A significant number
of pHPT patients have low calcium intake and suffer from vitamin deficiency. Thus, we adopted a policy of postoperative supplements
with calcium and vitamin D after parathyroid surgery. In this study, we investigated if this policy enhanced the postoperative
increase in bone density.
Patients/Methods Forty-two consecutive patients (83% female) were studied. The first 21 patients received no supplements, whereas the following
21 patients received 1,000 g calcium and 800 IU hydroxy D-vitamin daily (Ca–D group) for 1 year postoperatively. The patients were monitored with bone density and biochemistry pre-
and at 1 year postoperatively.
Results Preoperatively, the patients without vitamin D supplementation (non-Ca–D group) did neither differ in biochemistry, clinical
features, nor in bone density from patients in Ca–D group. Postoperatively, there was a tendency that patients in Ca–D group
increased their bone density, at all sites measured, in a greater extent than patients that did not receive calcium and vitamin
D supplementation.
Conclusion In conclusion, based on our results, it is difficult to give a recommendation of vitamin D supplementation in routine use
following surgery for primary hyperparathyroidism. Based on the present data, a calculation of sample size for a future randomized
controlled trial is presented. 相似文献
998.
999.
Jimmie Honings MD Henning A. Gaissert MD PhD Ad F. T. M. Verhagen MD Jos A. A. M. van Dijck PhD Henricus F. M. van der Heijden MD PhD Lya van Die MD Johan Bussink MD PhD Johannes H. A. M. Kaanders MD PhD Henri A. M. Marres MD PhD 《Annals of surgical oncology》2009,16(2):246-253
National epidemiologic data were examined to determine the eligibility for curative therapy in tracheal carcinoma. An expert
audit of primary tracheal carcinomas registered from 2000 to 2005 with the Netherlands Cancer Registry (NCR) included blinded
patient data and radiographic review to assess diagnosis and resectability. Actual treatment was compared with the opinions
of a multidisciplinary panel (Radboud panel) and a second reviewer. Of 101 NCR-registered primary tracheal carcinomas, the
Radboud panel diagnosis was metastatic disease or local extension of adjacent tumors in 34. Seventeen cases were excluded
for missing data. In 50 cases confirmed by panel and a second reviewer, actual treatment consisted of surgery in 12 (24%),
radiotherapy in 29 (58%), endobronchial treatment in 6 (12%), and observation in 3 (6%). Both panel and second reviewer identified
16 additional surgical candidates, a total of 28 (56%) of 50. Treatment recommendations of panel and second reviewer disagreed
in four cases (8%). One-third of NCR-registered primary tracheal carcinomas were misclassified nontracheal primary tumors
involving the trachea. A majority of cases meeting audit criteria for diagnosis and surgical resection was treated with other
modalities. Interreviewer disagreement was small. The audit of a national cancer registry suggests that incorrect diagnosis
and undertreatment are common in rare airway tumors. 相似文献
1000.
Leif I Havelin Anne M Fenstad Roger Salomonsson Frank Mehnert Ove Furnes S?ren Overgaard Alma B Pedersen Peter Herberts Johan K?rrholm G?ran Garellick 《Acta orthopaedica》2009,80(4):393-401
Background and purpose The possibility of comparing results and of pooling the data has been limited for the Nordic arthroplasty registries, because of different registration systems and questionnaires. We have established a common Nordic database, in order to compare demographics and the results of total hip replacement surgery between countries. In addition, we plan to study results in patient groups in which the numbers are too small to be studied in the individual countries.Material and methods Primary total hip replacements (THRs) from 1995–2006 were selected for the study. Denmark, Sweden, and Norway contributed data. A common code set was made and Cox multiple regression, with adjustment for age, sex, and diagnosis was used to calculate prosthesis survival with any revision as endpoint.Results 280,201 operations were included (69,242 from Denmark, 140,821 from Sweden, and 70,138 from Norway). Females accounted for 60% of the patients in Denmark and Sweden, and 70% in Norway. Childhood disease was the cause of 3.1%, 1.8%, and 8.7% of the operations in Denmark, Sweden, and Norway, respectively. Resurfacing of hips accounted for 0.5% or less in all countries. The posterior approach was used in 91% of cases in Denmark, 60% in Sweden, and 24% in Norway. Cemented THRs were used in 46% of patients in Denmark, in 89% of patients in Sweden, and in 79% of patients in Norway.Of the 280,201 primary THRs, 9,596 (3.4%) had been revised. 10-year survival was 92% (95% CI: 91.6–92.4) in Denmark, 94% (95% CI: 93.6–94.1) in Sweden, and 93% (95% CI: 92.3–93.0) in Norway. In Denmark, 34% of the revisions were due to dislocation, as compared to 23% in Sweden and Norway. Replacement of only cup or liner constituted 44% of the revisions in Denmark, 29% in Sweden, and 33% in Norway.Interpretation This unique common Nordic collaboration has shown differences between the countries concerning demographics, prosthesis fixation, and survival. The large number of patients in this database significantly widens our horizons for future research. 相似文献